1. Field of the Invention
The present invention relates to a projector apparatus that optically enlarges an image in a small display device formed by a liquid crystal panel, a cathode-ray tube, or the like to display the image in a large screen by projecting the image to a projected surface (screen). In particular, the present invention relates to a projector apparatus that is air-cooled inside.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2009-175404 discloses a technology as a first example of a related art projector. Japanese Unexamined Patent Application Publication No. 2009-175404 discloses a technique relating to an image projecting apparatus that illuminates image forming elements used to form an original picture using light emitted from a light source, and projects the light from the image forming elements to the projected surface. The image projecting apparatus includes a casing having an air intake that is provided with a dust-removing filter, a fan that draws air into the casing through the air intake, a duct that directs the air drawn through the air intake to a space containing the image forming elements, and an air channel chamber provided between the duct and the air intake. In addition, in the image projecting apparatus, the cross-sectional area of the air channel chamber at a connecting portion between the air channel chamber and the duct and perpendicular to an air flow direction into the duct is larger than that of the connecting portion.
Japanese Unexamined Patent Application Publication No. 2004-157347 also discloses a technology as a second example of a related art projector. Japanese Unexamined Patent Application Publication No. 2004-157347 discloses a technique relating to a projector. This projector includes a first filter provided in an air intake formed in an outer casing, the first filter being used to remove dust and the like from air drawn by a fan. In this projector, a filter unit that includes a second filter having an area larger than that of the first filter is removably mounted in the outer casing so as to cover the air intake from an outer side of the first filter.
However, the related art projector apparatuses are structured such that the air filter is disposed immediately inside the air intake and the air drawing fan is disposed inside the air filter. Since the air drawn through the air intake is directly drawn by the air drawing fan through the air filter and fed to an inner portion of the projector apparatus in this structure, an area of the air filter that can be allocated in this structure is only substantially equal to an area of the air intake. As a result, it is difficult to expand the area of air intake due to a size limitation of the apparatus casing. Expanding the area of the air filter typically results in an increase in the size of the apparatus casing. This poses a problem in that the size of the whole apparatus is increased.
In this regard, the first related art example disclosed in Japanese Unexamined Patent Application Publication No. 2009-175404 includes an optical system cooling fan, a lamp cooling fan, and a power unit cooling fan in order to air-cool an inner portion of an apparatus casing. The optical system cooling fan is used to cool optical elements such as liquid crystal panels, polarizing plates, and so forth and is connected to an air intake provided in an apparatus cabinet through a duct. The lamp cooling fan is used to cool a light source lamp and is connected to an air intake through a duct. The power unit cooling fan is used to cool a PFC power unit and a ballast power unit and is connected to an air intake through a duct as is the case with other cooling fans. The dust removing filter is provided in the air intake, which is used to remove dust from drawn air. By doing this, the dust-filtered air is separately supplied to each cooling fan through the ducts. Due to this structure, expanding the area of the air filter typically results in an increase in the size of the apparatus casing. This poses a problem in that the size of the whole apparatus is increased.
The second related art example disclosed in Japanese Unexamined Patent Application Publication No. 2004-157347 has a structure such that the second filter having an area larger than that of the first filter is arranged so as to cover the air intake from the outer side of the first filter. Due to this structure, expanding the area of the air filter typically results in an increase in the size of the apparatus casing. This poses a problem in that the size of the whole apparatus is increased as is the case with the first related art example.